Automatic telephone system



m 29, 19%. T, pbw LL 2,410,304

AUTOMATIC TELEPHONE SYSTEM Filed March 20, 1944 s Sheets-Sheet 1 LINE 00 63 I N V EN TOR.

W/A/Ffiffl T POWELL 7 HTTOIZ/VEY Oct. 29, 1946 W, POWELL 2,410,304

AUTOMATIOTELEPHONE SYSTEM Filed March 20, 1944 3 Sheets-Sheet 2 63 IVENTOR.

h/m/Few ZJOWEAZ" BY HTTOE/VEY @ct, 29, 194-6. w POWELL Q 2,410,304

AUTOMATIC TELEPHONE SYSTEM Filed March 20, 1944 3 Sheets-Sheet 3 INVENTOR.

Patented Oct. 29, 1946 AUTOMATIC TELEPHONE SYSTEM Winfred '1. Powell, Rochester, N. Y., assignor to Stromberg-Carlson Company, Rochester, N. Y.,

a corporation of New York 1 Application March 20, 1944, Serial No. 527,29&

5 Claims. (01. 179-18).

In conventional automatic telephone systems, there is provided an individual line relay for each line so that for each group of one hundred lines, one hundred line relays are required. a

In my Patent 1,540,419, granted June 2, 1925, there is disclosed a systememploying a lesser number of line relays than the; number of related telephone lines, to control the line switches individualto the several lines serving to connect these lines to idle trunks. In thepatented arrangement, since a line switch is individualto each line, there is not the necessity of looking out the remaining lines of a group'while one of said lines is being extended to an idle trunk, a necessary requirement where an all relay type finder is utilized. 1 i I The present arrangement, therefore, has for its purpose the utilization of primary line relays and secondary line relays, less in number than the number of lines in the group which they serve, together with certain cooperating relays whereby all relay line finders can connect idle trunks to calling telephone lines in an accurate, reliable manner with a substantial saving in cost of equipment. e

Specifically, the present invention comprises a. circuit arrangement'in which ten primaryline relays and ten secondary linerelays common to one hundred lines replace the one hundred line relays usually employed in a line finder system. While other supplemental relays common to this group of lines are required, the total number of relays needed for the mentioned group of lines is substantially less than the one hundred line relays now in current use.

For a clearer understanding of the invention, reference is made to the drawingsin which:

Figs. 1, 2 and 3, when arranged side by side in the order named, disclose a portion of a telephone system incorporating the invention.

For convenience in description, the present telephone system isassumed to have one hundred telephone lines although it will be understood that the invention not so limited but may include systems employing many hundreds of lines. With these one hundred lines of which only the line L is illustrated,"there are provided ten pri mary line relays designated Ito H] inclusive and a group of ten secondary'linerelays designated 20 to 29 inclusive. In addition, there are employed ten units lockout relays'30 to 39 inclusive and ten tens lockout relays 40 to 49 inclusive, together with ten multicontact relays 50 to 59.

' With this brief outline of the system,it is believedfthat'the invention willjbest be understood 2 by describing the operation of extending a calling telephone line, such as line L, to an idle link. When the subscriber at the substation on line L lifts his telephone receiver to close the telephone switch contacts (not shown) thereat, a circuit is closed from the positive pole of battery, baclrcontact and armature of the cut-off relay lill, thence over the lower side of the line L, through the mentioned switch contacts now closed, thence over the upper side of the line, armature and back contact of cut-off relay tilpa'rmature 62 and back contact of the multicontact relay 50, conductor 63, winding of the primary line relay W, to the negative pole of battery. Relay I0 is energized in this circuit and at its armature 64 and front contact, it closes a circuit from the positive pole or" battery, conductor 65, winding of the tens lockout relay 49, through a back contact and continuity spring 66 of this relay, and also through the back contact and continuity spring 61 of this relay and thence through the backcontacts and continuity springs, similar to 61, of relays 4! to 49 inclusive, resistor 68, to the negative pole oi. battery. Relay 4!! is thus energized to close a'substitute circuit for itself through its continuity spring 61 and armature, and thence through the mentioned back contacts and continuity springs, such as 61, of the relays 4| to 49 inclusive, resistor 68 to the negative pole of battery. Relay 4!! is maintained operated in this circuit for the time being and at its back contact and continuity spring 61, it interrupts any of the possible operating circuits for the relays M to 49 "so that none of them can be operated at this time.

As soon as the relay 4!! is actuated, it completes an operating circuit .for the multicontact relay 50, Which circuit extends from the negative pole of battery, winding of relay 5% tothe positive pole of battery at the lower armature and front'contact of relay 4E). The relay 50, when thus operated, switches all ten telephone line circuits, appearing in the level which it controls, from pri-, mary line relay It] to the secondary line relays 2D to 29 inclusive. The closed circuit'across the telephone linef'L is thus disconnected from the primary line relay H1 and is extended to include the winding of the secondary line relay 2!). vThe relay 20 operates and closes a locking circuit for the "relay 40 from the positive pole of battery, armature l0 and front contact of the relay 20, conductor (Linner front contact, armature and winding of relay and thencethrough the con tinuity springffifi; and armature of relay 40, through continuity springs and back contacts,

such as 61, of relays 4| to 49 inclusive, as previously described, resistor 68, to the negative pole of battery. Thus, a locking circuit is completed for holding the slow releasing relay 40, before it has time to release when its initial operating circuit is interrupted by the release of primary line relay Iii. The release of relay l takes place when the relay is disconnected from the line L, as described above. It should be mentioned that the relays 40 to 49 inclusive need not be especially slow in releasing but just slow enough to prevent releasing in the event that a secondary relay, such as 29, is slow in operating, after a switching relay, such as 58, disconnects the line circuit L from the primary line rela l0.

When the secondary line relay 2!! is operated, as above described, it closes a circuit for actuating the units lockout relay 30. The. circuit for operating the relay 30 extends from thepositive pole of battery, armature l2 and front contact of relay 2|}, conductor 73, winding of the relay 38, its continuity spring and back contact 14, its back contact and continuity spring i and thence through the back contacts and continuity springs similar to at each of the relays 3| to 38 inclusive and through the resistor 15, to the negative pole of battery. It will be noted that the relays 39 to 39 inclusive are electrically interlocked to prevent the operation of more than one of them at any one time. The operation of the relay Sli closes its armature l9 and front contact thereby applying ground to the allotter start wire 8&1, to complete a circuit including start wire 80, armature and back contact of allotter relay 8|, Winding of slow releasing relay 82, to

the negative pole of battery. Allotter relay 82, when energized, completes an energizing circuit for the multicontact allotter relay 83 (Fig. 1), from the negative pole of battery, winding of re lay 83, conductor 85, inner armature and front contact of relay 82, back contact and armature of relay 8|, conductor 88 to the positive pole of battery at the front contact and armature 19 of relay 38. The mentioned relays 8|, 82 and 83 constitute part of'an allotting means which serves to assign for use, an idle link or trunk with its relay finder, of which only the tens finder relay as (Fig. 3) and the units finder relay 81 thereof, are shown.

With the multicontact allotter relay 83 (Fig. 1) now operated and with the multicontact marker relay 58 energized, as above described, the tens finder relay 8'5, has its operating circuit completed. This circuit extends from the negative pole of battery, winding of relay 36, conductor 88, front contact andarmature of relay 33, front contact and armature of relay 50, to the positive pole of battery. The finder relay, when thus operated, locks itself in this condition, through its inner front contact and armature, holdin conductor 90, which is connected to the positive pole of battery, through front contact of relay I82, which will be energized in a manner to b described and will thereafter remain energized as long as the telephone connection. under consideration is maintained. Similarly, with the allotter relay 83 operated and with the marker relay 30 '(Fig. 2) also operated, the units finder relay 8'! (Fig. 3) is energized from the negative pole of battery, winding of'relay 81, conductor 89, front contact and armature of relay 83, conductor 9i, armature 92 and front contact of relay 3|],Tto the positive pole of battery. Relay 8'l,.-wheniener gized, locks itself operated through its. front con-'- tact and armature, over the holding conductor 90. .As soon as the tens finder relay 86 and the units finder relay 81 are operated, the tip, ring and sleeve conductors 94, 95 and 96 respectively are extended to the tip, ring and sleeve conductors 91, 98 and 99 respectively of a link such as the connector link (Fig. 3). When this takes place, the relay N10 is operated over the mentioned tip and ring conductors and the calling line circuit. Relay I 00 closes an obvious circuit for the slow releasing relay H, which in turn effects the operation of the slow releasin relay )2. As soon as the link, indicated in Fig. 3, is seized,the allotter relay 8| is energized over its lower winding and conductor 85. When thus energized, relay 8|, locks itself operated through its upper armature and front contact. Relay 8| at this time extends the starter wire 80, to a further extension 80a of this wir having relays similar to 8|, 82 and 83 related to another trunk or link.

Relay )2, when operated, completes a circuit from the positive pole of battery through the sleeve conductors 99 and 96, Winding of the cut off relay 60 to the negative pole of battery. This circuit operates the cut off relay to open its armatures and back contacts and thereby releases relay 29. Relay 2t at its armature l2 and front contact opens the holding circuit for the units lockout relay 3D. The release of the lookout relay 3!), makes all of this series of units lockout relays again available for use. Relay 30 at its armature i9 and front contact, opens the starter wire including conductor 80. Also, when relay 23 releases, it opens at its armature Hi and front ccntact, the circuit including conductor H, which has been holding operated, the tens lockout relay 4!). Relay 4! releases and thereby restores the series of tens lockout relays for subsequent use. The release of the relay 4!! in turn effects the release of relay 5%).

Calls on any one of the remaining telephone lines of the hundred line group can be extended in a similar manner, It should be pointed out that since the line circuit, such as L, controls the operation of a primary line relay, such as 10, and a secondary line relay, such as 20, and since these relays in turn. control the tens and units lockout relays, suchas 30 andf lfl respectively, there is no possibility of a tie-up condition, even when several calls are initiatedat exactly the same time. This desired condition prevails since only one tens lockout relay, and only one units lockoutrelay can be operated at any one time, irrespective of the number of simultaneous calls initiated. These operated relays are released after a given line has been connected to a link or trunk inorder to eifecta separate. and distinct marking and lockout condition for the next telephone line to be found.

What I claimis:

1. In a. telephone system, a. plurality of telephone lines, primary relays and secondary relays common to said telephone lines andlessin number than the numbers of said lines, means responsive to the extension of a call over a certaint'elephone line for operating incombination a given primary relaysandfla given secondary relay, said combination being individual tosaid certain telephone line, and. finder switching means controlled by the operation of said given primary relay and by' the operation of said given secondary relay for seizing said'certaintelephone line.

'2- Ina telephone system,.a.pl urality of groups of incominglines, aprimary relayfcommon to each group of lines, asecondary relay common'to a line in each group, means responsive to the extension of a call over a certain line for actuating a primary relay and a, secondary relay both common to said certain line, and finder switching means controlled by said last-mentioned primary and secondary relays for seizing said certain line.

3. In a telephone system, a plurality of telephone lines, primary relays and secondary relays less in number than the numbers of said lines, said primary and said secondary relays being controlled over. said telephone lines, a. chain of tens lockout relays and a chain of units lockout relays, said lockout relays being common to said telephone lines and being selectively operated under the control of said primary and secondary relays, means including certain of said lockout relays for marking said telephone lines in succession when calling, and finder switching means operated responsive to the marking of a calling telephone line for seizing that line.

4. In a telephone system, groups of incoming lines, a primary relay common to each group of lines, a secondary relay common to a line in each group, a first chain of lockout relays corresponding to said groups of lines, a second chain of lockout relays corresponding to the lines of said secondary relays, the operating circuit of each relay of a chain being controlled by each of the remaining relays oi a chain whereby the operation of any relay of the chain temporarily disables the remaining relays thereof, means responsive to the extension of a certain incoming line for operating the primary relay related thereto, means controlled by the operation of said lastmentioned relay for operating a corresponding lockout relay of said first chain, a series of multicontact relays corresponding to and operated by said first chain of lockout relays, means including an operated multi-contact relay and said incoming line for effecting the operation of a certain one of said secondary relays, said secondary relays controlling the operation of a certain lockout relay of the second chain, and finder switching means controlled by the operated multicontact relay and by the operated lockout relay of the second chain for seizing said incoming line.

5. In a telephone system, groups of incoming lines, a primary relay common to each group of lines, a secondary relay common to a line in each group, a first chain of lockout relays corresponding to said group of lines, a second chain of lockout relays corresponding to the'lines of said secondary relays, the operating circuit of each relay of a chain being controlled by each of the remaining relays of the chain whereby the operation of any relay of the chain temporarily disables the remaining relays thereof, means responsive to the extension of a certain incoming line for operating the primary relay related thereto, means controlled by the operation of said lastmentioned relay for operating a corresponding lockout relay of said first chain, a series of multicontact relays corresponding to and operated by said first chain of lockout relays, means including an operated multicontact relay and said incoming line for eflecting the operation of a certain one of said secondary relays, said secondary relays controlling the operation of a certain lockout relay of the second chain, a plurality of finder switching means, means for allotting finder switching means for use, means including an operated lockout relay of the second chain for operating said allotting means, and means including the operated multicontact relay and the operated lockout relay of the second chain for causing the allotted finder switching means to seize said certain incoming line.

WINFRED T. POWELL. 

